Conventional image-forming devices, such as laser printers, commonly include a process cartridge that is detachably mounted in a main casing of the image-forming device. The process cartridge includes a photosensitive drum on which electrostatic latent images are formed.
This type of process cartridge also induces a charger for charging the photosensitive drum, a transfer roller for transferring a visible image formed by developing an electrostatic latent image onto paper, and a cleaning member for removing paper dust deposited on the photosensitive drum after the transfer process. With this configuration, a charging bias is applied to the charger, a transfer bias to the transfer roller, and a cleaning bias to the cleaning member.
To achieve this, a power supply is provided in the main casing of the image-forming device, and a terminal member is provided in the process cartridge for applying a bias to each of the charger, transfer roller, and cleaning member. When the process cartridge is mounted in the image-forming device, the terminal member is capable of contacting or separating from a fixed contact point connected to the power supply provided in the main casing. The power supply applies a bias from the fixed contact point to each of the charger, transfer roller, and cleaning member via the terminal member.
One such process cartridge disclosed in U.S. Pat. No. 6,571,070 includes a cartridge-side contact point provided on an outside surface of the process cartridge that can be electrically connected to a contact point on the main assembly of the apparatus when the process cartridge is mounted in the apparatus.